DE3741780A1 - MAGNETIC THEFT OR BURGLAR SECURITY SYSTEM AND SENSOR METAL ELEMENT SUITABLE FOR THIS - Google Patents

Abstract

Arrangement for safeguarding objects located in a room provided with at least one room outlet, particularly a (self-service) sales location such as, for example, a supermarket, against theft or against burglary, in which the objects to be safeguarded are in each case provided with at least one magnetically activatable metal sensor element, comprising a first device, to be arranged at each room outlet, for generating a magnetic field in the area of which a magnetically activated metal sensor element in each case arranged at an object to be safeguarded generates a signal when a limit field strength value is exceeded, and a second device associated with the first device, by means of which a signal is to be detected and to be supplied to an alarm device in order to trigger an alarm, the metal sensor elements (8) in each case being constructed in such a manner that they generate in the active state in an area of the magnetic field in which the field strength is greater than a lower limit value an atypical signal which is not generated by other metallic objects when magnetically excited but is only generated by a magnetisable object when the latter has been selectively subjected to a special treatment; and in that the first device consists of at least one (first) field coil (9) having a preferably horizontal centre axis (16) which annularly surrounds the relevant room outlet (1) and the height (H) and width (B) of which is constructed in such a manner that a person can pass it in the direction of its centre axis (16), and a metal sensor element suitable for this purpose and the use of a Wiegand wire as metal sensor element for a safeguarding system. <IMAGE>

Description

The invention relates to a system or an arrangement for securing in at least one room outlet pointing room, especially a (self-service) ver shop (such as a supermarket), located Items against theft or burglary, the objects to be secured each with at least  a magnetically activatable sensor metal element are, with a first to be arranged at each room outlet Device for generating a magnetic field, in the Be submit one each to an object to be secured associated, magnetically activated metal sensor element If a field strength limit is exceeded, a detect bares signal generated, and with one of the first device assigned second device, by means of which he detected signal and when it occurs a An alarm device must be sent in order to trigger an alarm.

The invention further relates to a suitable one Sensor metal element and the use of a section a Wiegand wire as a sensor metal element for a mag netic security system of the type in question here.

If there is talk of a "space outlet" above or below, then it is not necessary - in particular when the system according to the invention is used as theft protection in a sales or exhibition facility - to be an exit of the space in question, which either leads to the outside or to another room and is accordingly embedded in a boundary wall of the room in question. Rather, it can be just within the room in question (for example, at a cash desk), appropriately be limited passage or the like. act as he is generally referred to in the relevant field as a control gate, i.e. a passage that people have to pass through to leave the room or a delimited part of the room if they want to leave the relevant room or part of the room. In contrast, when the system according to the invention is used as an intrusion security system, it will generally be a conventional entrance / exit and, moreover, windows, floor or cellar hatches and the like. act, i.e. room outlets that are present in a wall, the ceiling or the floor of the room to be secured.

A backup of ready to sell in retail outlets held against theft is not only relative high-quality goods, but also with low-value counterparts were offered, since unfortunately such Property offenses are not isolated cases that are about higher quality goods are limited. Rather, it works based on corresponding investigations, assume that, for example. in so-called supermarkets or similar sales outlets, in which the goods kept in stock are always on demand by customers (usually in a shopping basket or cart) taken and then paid at a cash register by Theft of lost goods affects practically everyone offered goods and in total more than 1% of the total sales. This size is not the least in view of the relatively small profit margins of such Sales outlets are therefore extremely high and require appropriate Countermeasures.

In addition to various other attempts at realization an effective security of goods against theft known systems on a magnetic basis been, however, both technically (including Lich their effectiveness) as well as economically despite the long-standing need still in are extremely unsatisfactory. The are suitable well-known magnetic anti-theft systems often already because of the investments to be made with regard to the requ  other facilities on the one hand and the ones to be used On the other hand, sensor elements from the outset only for limited use. Because if, for example, the average profit margin of a supermarket for 1% of the goods value lies and the value of a certain commodity e.g. DM 5, - so it is obviously economical nonsensical, such an object with a (not secure reusable) sensor metal element whose Procurement costs amount to 6 Pfg. And thus in the Size of the profit to be achieved. That is before standing example in no way out of thin air, son which is even at the lower end of the cost scale for the like sensor elements. Other sensor metal elements for Use with magnetic theft protection systems cost even a multiple (e.g. approx. DM 0.25) and leave accordingly, at best for economic reasons for very high quality goods with a corresponding value deploy. The well-known anti-theft systems However, magnetic bases also show how already indicated significant technical shortcomings on how will be explained in more detail below. There there is a particularly serious shortage among others in this, that false alarms occur relatively often. False alarms ver however, do not only hesitate the planned quick sale process (and thus lead to a corresponding Annoyance of customers), but affect very often also suggest that customers who are due to a mistake alarms have been exposed as a supposed thief and undergo a corresponding review procedure need, one with such an anti-theft system avoid the designated sales point in the future because they The risk of a false alarm is too great and that with an - if equally incorrect - suspicion-related circumstances  are uncomfortable, so doing a sale would be a not inconsiderable one over time Sales are lost.

In known anti-theft systems in here The genus in question consists of one each securing object to be attached to sensor metal elements each from a metal strip, which from a high perm ablen metal or a corresponding metal alloy with pronounced rectangular hysteresis loop. Here the metal strips forming the sensor elements must also be used a separate security label on one to be secured Item to be attached, because the usually for Price tags used are too small to be awarded to be provided with such a metal strip can. A length of 7 cm, for example, is Metal elements of common systems required to which he wanted to be able to generate signals at all. Be there immediately referred to the fact that due to this necessary dimensioning and thus necessary separate labeling the security costs at a such a system can be further increased by that an additional operation is required to get one object to be secured with such a sensor element to provide.

Another disadvantage of such or similarly trained Sensor elements is that because of their size are relatively easily recognizable by potential thieves, and themselves accordingly easily discover and, if necessary, by tearing or the like. have it rendered ineffective. With certain sensor elements for be knew electromagnetic theft protection systems where  the sensor elements in the manner of a printed circuit are trained on a corresponding fuse label is attached, there is not even a need for an Ent away from the sensor element to make it ineffective. Rather, it is sufficient for this if individual Line sections using a sharp object be cut, for which a fingernail may already be can suffice.

Will be with such an anti-theft system ver with a magnetically activated metal sensor element seen object to a room outlet, in a supermarket or the like, for example one arranged adjacent to a cash register Control gate brought to by means of an appropriate A magnetic (alternating) field is generated, in this way, in a corresponding facility, the consists essentially of an induction coil, due to the non-linear hysteresis loop of the material of the Metal sensor element etc. Harmonics induced by means of evaluated by a suitable electronic filter device can be, so that when appropriate Ober occurs waves an acoustic and / or visual alarm is triggered (if necessary, the Room outlet are closed), if a corresponding ge Secured object unauthorized from the room in question Will get removed.

On the other hand, if a correspondingly secured object is properly paid according to and only afterwards by a corresponding armored outlet, so its magnetization deactivated during or after payment so that when passing the room outlet there are no harmonics that give a signal for unauthorized removal of a secured object deliver.  

Specifically, there is the establishment of such a known one The anti-theft system, in addition to the already again brings mentioned strip-shaped sensor metal elements, the the induction coil forming the take-up coil and the filter electronics from an excitation coil, which the electromagnetic alternating field generated. This drives him out of you soft magnetic metal existing security strips up into saturation and then generates in it due to the Alternating magnetic reversal processes, which with the In induction coil are detected. It is then by means of Filter electronics expediently below the fundamental frequency and only the (generally between the second and twentieth harmonic, often up to the 100 kHz Area-reaching) harmonics, being important is that these harmonics occur even at relatively small Er excitation field strengths are excited with which the previously known Systems work that these are generated and trained evaluating harmonics but if possible from signals stand out, not from metal sensor elements, but from Objects are created that a customer may have with them leads or duly declared as a commodity and paid. In order not to meet them one hundred percent anyway to be able to meet real requirements, must the magnetic material of such a sensor metal element-serving security strips both extremely high permeable as well as pronounced rectangular with respect to it Be a hysteresis loop. These requirements are met by certain Co-rich, soft magnetic, amorphous alloys well fulfilled, which are almost free of magnetostriction. Here enables a combination of a magnetically active strip with a magnetically semi-hard material, the backup Function of a sensor metal element with authorized Mit an appropriately secured article is disabled  to put. For this purpose, for example, the semi-hard part of the metal strip magnetized by an external field and in this way linearizes the characteristic of the magne table active strip or strip part, which the in the event of unauthorized transport, deliver the desired signal Harmonics are reduced in their amplitude so much that they are no more than harmonics from the filter electronics are recognized and no longer trigger an alarm signal. Unfortunately in this respect it is not uncommon for the ent speaking wish and it comes up despite corresponding opening Magnetization through misinterpretation to trigger a mistake alarm.

The present invention is based on the object Avoiding the aforementioned and other disadvantages To create a security system of the type described at the outset, which is both technical and economical Regarding the requirements to be met. In doing so from a technical point of view, on the one hand be that an entrainment of an illegitimate person Subject (at least with a sufficiently large stati probability) is actually determined, on the other hand with a probability bordering on certainty triggering a false alarm is avoided. In from an economic point of view with the invention The necessary investments with regard to the necessary facilities and in particular the he significantly reduce the required sensor metal elements be, on the one hand by correspondingly low loading acquisition costs and on the other hand through a considerable ver reduction of the installation costs (for example by the fact that a Sensor metal element itself with a price tag on one can be attached to the object to be secured). Furthermore  the sensor metal elements according to the invention for the security system according to the invention (due to possible small size) of potential thieves as bad as possible Recognize or locate and save if found Let power set. Finally, the invention Security system itself with corresponding advantages if necessary can be used as a burglar alarm system. Another Part of the basis of the present invention position lies in a new use of a further Wiegand wire described in detail below, such as this will be described in more detail below.

According to the invention, this object is initially achieved once in that the sensor metal elements each look like this are formed so that they are active in one area of the magnetic field in which the field strength is greater than one lower limit (= ignition field strength) a clear signal generate which of other magnetic or magneti objects in a magnetic field is not generated, but by a magnetizable counter was only generated if it was a special one Treatment has been undergone, and that to every room outlet arranged first device from at least one (First) field coil with a horizontal central axis, wel che surrounds the relevant room outlet in a ring, and their Height and width is designed so that a person in Can cross direction of its central axis.

In order to evaluate the signal to be generated using the i.a. essentially from a filter electronics or the like. existing Simplifying the second device is known in itself Way provided that that generated by the first device  Magnetic field is an alternating field, so in this way one is to generate quasi-stationary signal, which he can be evaluated significantly better than a singular signal.

According to a most preferred embodiment of the present invention, the system is designed such that the signal to be detected by the second device - preferably at least one induction coil of the second device - is a pulse that is preferably asymmetrical for reasons explained in detail below.

A most preferred embodiment of an inventive Sensor metal element is in its design as Wiegand wire, whose length prefers (only) about 5 up to 20 mm and especially for immediate use in connection with usual price tags only approx. 1 cm is, the diameter being about 0.15 to 0.4 mm can and with a most preferred embodiment of the lying invention is about 0.25 mm.

The so-called Wiegand wire is a magnetic one Wire storage element, which be from the literature known Wiegand effect, which consists in that an existing of certain ferromagnetic material Wire that has undergone certain treatment its direction of magnetization changes spontaneously when it moves from a magnetic field is applied, the field strength exceeds a certain limit (= ignition field strength). A Wiegand wire basically consists of two sections with different magnetic properties, the Coercive force of one section significantly above the Ko the other section's tensile strength, although the wire its cross section is essentially uniform  has chemical composition. For example, becomes a wire made of a ferromagnetic material with a fine grain structure subjected to a longitudinal tension sufficient to support it to lead permanently, and then a cyclical torsion exposed to stress, after completing the longitudinal voltage is removed from the wire, this creates a Wiegand wire, in which the sections are different Coercive force on the one hand from its jacket section and on the other hand, consist of its core section, like this one For example, is described in DE-PS 21 43 326.

The spontaneous change of the Magnetization direction of a Wiegand wire at Über stride a certain ignition field strength, which in the Lite rature also as a large Barkhausen discontinuity or large Barkhausen jump is induced in one way a nearby voltage induction coil impulse, which is about the shape of a Gaussian bell curve points, and can have a half-value width of, for example, approximately 20 µs.

Since it is clearly intended for the control and evaluation is moderate, not just a singular dynamic signal to generate, as is the case when a Wiegand wire is brought into a constant magnetic field, whose field strength exceeds the ignition field strength, is with the first Device for generating a magnetic field preferably in a periodic magnetic change known per se field generated, so by means of such excitation quasi-stationary signals are to be generated. Such a change field is to be generated with a frequency generator Frequency in a preferred embodiment of the present Invention is in the range of 400 to 800 Hz, the  Frequency generator does not have to be in constant operation, but preferably only to be switched on automatically when a person approaches him, and therefore preferably himself active again when the person turns away from him away. This is due to the simplest circuitry To implement measures (e.g. by means of a light barrier).

As already from the above explanations for the permanent specialist with sufficient clarity to stop may have come under pressure, it is the so-called Wiegand wire around a sensor metal element, which is in the frame the present invention is particularly suitable, namely both technically and economically Points of view. However, this is not meant to be an expression brought that there are no other possible configurations of sensor metal elements suitable for the invention, the little in technical and / or economic terms offer almost the same benefits.

For example, the one from the company Vacuumschmelze GmbH Hanau Berlin produced and sold so-called impulse wire Element which is the highest within the scope of the present invention is to be used advantageously. With this so-called impulse wire is a composite wire with an inside lying switch core through a jacket material under tension voltage is kept. Is parallel to the composite wire a permanent magnet wire preferably of the same length and arranged about the same diameter, with usual Ab measurements of such pulse wires with a diameter of about 0.1 to 0.2 mm and a length of about 10 to 20  mm is sufficient for use as a magnetic sensor. The give like impulse wires (without power supply) as mag netic switching element voltage pulses up to 2 V, where only a magnetizing to trigger the pulse Field of only about 20 A / cm is required and the pulse half-width lies in the range of approx. 12 µs. Such Pulse wires have so far been used to record magnetic fields as well as for storing information.

As has already been explained above, there is little arranged in each case at a room outlet at least from a field coil, which among other things is dimensioned that their height is about 2 m (e.g. 2.2 m) and their width is about 1 m (for example 0.8 m), so that one person bores the field coil can go through if this, as it were, the space outlet surrounds in a ring, the lower leg of the field coil conveniently sunk an anti-theft system is sunk in the floor of the room in question and when using the security system according to the invention as a burglar alarm system on the other legs of the Field coil in a wall or ceiling of the room in question can be let in.

It has been shown that a leg cross-section of a field coil of approximately 5 to 15 cm ² with a number of turns of a field coil consisting essentially of copper wire of approximately 100 to 200 turns is completely sufficient to be manageable in size and above all with other electrical values a Wiegand wire of sufficiently small dimensions to achieve the desired effect.

When arranging only one field coil in a room outlet ver with a non-deactivated Wiegand wire the object that was taken away and then taken illegitimately be shown if the longitudinal axis of the Wiegand wire essentially with the vector of the field coil exciting magnetic alternating field essentially over agrees, so that in such an arrangement thus be more than a third of all random spatial positions formed as a Wiegand wire sensor metal element Security detected and reported and accordingly a thief Experience has shown that not only a certain point of sale once haunted regularly, statistically every third until the second theft is determined.

In order to increase reporting security, namely to double it, can the first device assigned to a room outlet device (at least) have a further second field coil, whose central axis is at an angle to the central axis of the first field coil runs. The central axes of the first run and the second field coil perpendicular to each other, so that is another good third of all conceivable too due positions of the sensor cable designed as Wiegand wire Metal element to capture, and a hundred percent after White security can be realized by the fact that if necessary, a third field coil is also provided, the Magnetic vector perpendicular to the magnetic vector of the first and second Field coil runs. Since in particular the arrangement of a third Field coil in view of the fact that it happens to one Arranging the room outlet would present certain difficulties can provide the same security of evidence but can also be achieved in that a to be secured Object is provided with several sensor metal elements, whose longitudinal axis is perpendicular to each other. This  requires a greater effort, but it does especially with higher quality goods, if necessary can be worthwhile and is also economically justifiable if one considers that a sensor designed according to the invention Metal element costs only about 0.5 Pfg. required, which is about 2 to 3 orders of magnitude (!) smaller is as comparable systems for sensor metal elements.

Becomes a sensor metal element designed as a Wiegand wire premagnetized and does not exceed the ignition field strength an upper limit value, for example in the case of an intended Ignition field strength of 16 A / cm does not exceed 25 A / cm, so it is from an active sensor metal element at Beauf impact by the alternating magnetic field in the second Device generated pulse image asymmetrical; the positive The momentum is (significantly) higher than the negative one Impulse or vice versa. In contrast, are more positive and more negative Equally large pulse in demagnetized state. This effect is an excellent way to use it as a Wiegand Wire-formed sensor metal elements in the Invention deactivate the appropriate security system, which then happens if an appropriately secured item after payment is legitimately spent through a room outlet.

As has already been indicated above, there is second device of the security system according to the invention essentially with at least one induction coil preferably downstream filter device. It did turned out to be particularly useful if on two parallel legs of each field coil each have an induction Coil is arranged, wherein the induction coils make sense are fully oriented to change the magnet implement field whose vector is parallel to the central axis of the Field coil or to its magnetic vector runs.  

The induction coils are preferably low in their own capacity without a metal core.

The filter device downstream of the coils, by means of which signals generated by a sensor metal element filter (or filter other signals and the signals leading to the triggering of an alarm), A computer can be assigned or assigned to the process sequence determined, whereby the arrangement can be made so that the computer (e.g. by means of a light barrier) to acti four is when a person approaches a room outlet, that the computer then controls the frequency generator to put it into operation, and that the computer continues to a reception of signals not always for the off solves an alarm if it is somehow something Pulse signal is reported (like this in the configuration of the present invention may well be the case), but that he first checks the probability that these signals are actually from a sensor Signals generated metal element. This can in particular especially when using a Wiegand wire for the Aus Formation of the sensor metal elements according to the invention in excellent way that the computer the Ampli ratio of positive and negative impulses checks the ones in the induction coil / coils due to the magne generated by the field coil / coils table alternating field with the respective magnetic reversal are generated, with the further reduction of errors alarms an alarm is only triggered if a before given amplitude ratio of positive and negative Amplitude (or vice versa) is reached or exceeded.  

If you want to completely rule out false alarms, you can to program the computer so that an alarm only occurs is triggered when this amplitude ratio, for example 2: 1 or, for example, 3: 1.

The total investment costs for an inventive Security systems are compared to comparable known ones Systems low. Among other things, this achieved in that it is easily possible for everyone to be secured or secured room outlets of a room only one Computer and only one frequency generator to use. Because usually do not enter, for example, in a supermarket all customers who are currently at a cash register and thus in front of a room outlet (control gate) leave at the same time, and it is even less likely that several thieves have a room outlet at exactly the same time happen. Accordingly, it is sufficient if the computer at which can be a single board computer, the field coil (s) from a central frequency generator Electricity is supplied when a customer visits the room in question exit is approaching, especially since there are several room outlets can be controlled at the same time, since a measuring process takes only a fraction of a second each. Accordingly are only small for a room exit to be secured at least one field coil and at least one induction coil required, although it may also be useful if every room exit to be secured or secured separate filter electronics is assigned.  

Preferred configurations of the present invention are described in subclaims.

In particular, the function and operation is shown below on an embodiment with reference to a strong schematic drawing explained further. It shows:

Fig. 1 is a schematic representation of a check gate arranged at a checkout in a supermarket, wherein in the upper left part of Fig. 1 a secured object is partially enlarged in perspective, seen in the direction of arrow I in Fig. 2;

FIG. 2 is a top view of the illustration according to FIG. 1 seen in the direction of arrow II in FIG. 1;

.. Seen a section through the representation according to FIG 1 in the direction of the section line III-III Fig 3, seen therefore a side plan view of the control gate forming a Raumauslaß in the output direction;

Fig. 4 is a plan view of a price tag (approximately in original size) for the goods, the price tag also forms the security label and contains a sensor metal element designed as Wiegand wire, seen in the direction of the arrow IV in FIG. 5; and

Fig. 5 seen a side view of the price / security label according to FIG. 4 in the direction of arrow V in FIG. 4.

The Figs. 1 to 3 of the drawings show the application of a security system according to the invention as theft backup system in a supermarket, only designed as a control gate 1 Raumauslaß is exemplified by the.

The objects to be secured, which are goods 2 in the present case, which have been taken from a customer 3 corresponding inventory (e.g. shelves) in order to purchase them, will be the customer 3 when approaching one the check gate 1 pre-arranged cash register 4 placed on a conveyor belt 5 and fed to the cashier 6 , who types the corresponding prices, which can be found on a price tag 7 , into the cash register 4 and settles the purchase amount with the customer 3 .

The price tags 7 are shown in FIGS. 4 and 5 approximately in original size. They each consist of a fixed stick-on paper label 2 the product in question, on whose lower side a serving as a sensor-metal element 8 portion of a Wiegand wire is fixed. Already at this point it should be pointed out that the sensor metal elements 8 could possibly also be arranged within the goods 2 or their packaging, so that they are not recognizable by customers 3 at all.

In the area of the control gate 1 forming a space outlet, a field coil 9 is arranged, which is indicated in FIG. 1 with a dash-dotted line. As can be seen in particular from FIG. 3, the field coil 9 surrounds the control gate 1 in a ring. Its height H is 2.2 m and its width B 0.8 m, so that a customer 3 can easily pass the control gate 1 after the billing process.

The in stock in the supermarket, offered for purchase goods 2 are each provided with at least one security label, which also forms the price tag 7 . This is the case for goods 2.2 and 2.3 (see FIGS. 1 and 2), while goods 2.1 are provided with three security labels 7 (according to FIGS. 4 and 5), the sensor consisting of a Wiegand wire -Metal element 8 in its longitudinal extent according to the arrows x or y or z recognizable in the top left in FIG. 1 (there the goods 2.1 are partially drawn out in perspective in an enlarged view), the directions x , y and z in each case are perpendicular to each other.

The Wiegand wires serving as sensor metal elements 8 are magnetized in their active state. This activation state is then transferred to a deactivated state when properly billed (since the anti-theft system should not trigger an alarm when properly purchased) by demagnetizing the Wiegand wires serving as sensor metal elements 8 in the area of the cash register 4 will. For this purpose, an initially relatively strong magnetic alternating field is generated in the area of the conveyor belt 5 by means of a field coil 10 indicated with a dash-dotted line in FIG. 1, which in the direction of the control gate 1 is continuously reduced in strength, so that the de-activation of the sensor metal elements 8 takes place automatically when properly purchased. In order to prevent goods 2 carried by a customer 3 from being deactivated with respect to their sensor metal elements (s) 8 , the field coil 10 is shielded from the passage 11 running parallel to the cash register 4 .

The entire security device is (only) switched on when a customer 3 approaches the area of the cash register 4 . By crossing a light barrier 12 (see FIG. 2), this causes a single-circuit computer 13 to be switched on , which works for several (possibly all) control gates 1 of the supermarket in question and initially causes that a frequency generator 14 , which also works for several (possibly all) control gates 1 of the supermarket, is put into operation. The frequency generator 14 draws its power supply from the three-phase network and generates a sinusoidal voltage, which is a maximum of 67 V in the exemplary embodiment shown. It delivers a peak current of 15 A. The alternating frequency generated by the frequency generator 14 is approximately 600 Hz. The frequency automatically regulates the system to the resonance frequency of the field coil 9 .

The inductive resistance of the field coil 9 is compensated for by an appropriately dimensioned capacitance, a value of 600 Hz corresponding to the frequency generator 14 being selected as the resonance frequency. Since the capacitance is composed of discrete components which are subject not only to a certain tolerance but also to a certain aging, the resonance frequency cannot always be set precisely.

In order to nevertheless achieve a minimum resistance and to generate a maximum magnetic field, it has been provided, as has already been indicated, that the frequency generator 14 automatically settles to the actually existing precise resonance frequency.

The induction coils 15 , 15 arranged at a height h of 0.9 m on the two vertical legs of the field coil 9 are also oriented in such a way that they convert magnetic field changes, the vector of which points in the direction of the arrow 16 . The induction coils 15 , 15 are designed so that they have the lowest possible own capacitance and do not contain a metal core.

If an object 2 provided with an active sensor metal element 8 is not deactivated in the area of the cash register 4 (i.e. by means of the magnetic alternating field generated by the field coil 10 in the area of the conveyor belt 5 ), since the customer concerned does not place it on the conveyor belt 5 for billing , but for example in a pocket, under a coat or the like. leads in an illegitimate manner, and this customer 3 crosses the control gate 1 and thereby reaches an area in which the magnetic alternating field generated by the field coil 9 exceeds the intended ignition field strength of 17 A / cm (on this occasion it should be noted that the leg cross section of the field coil 9 is about 8 cm ² , and that the field coil 9 has 150 copper wire windings that can easily be loaded with a peak current of 15 A, the internal resistance being 4 Ω, the magnetic field in the center of the coil 17 ( s. Fig. 3) ie inside height of 1.1 m above the ground 18 and about 0.4 m from the respective side edge ent removed weakest is), the frequency generator 14 via the set of the light barrier 12 in transition calculator 13 already in operation and the Wiegand wire (= sensor metal element) 8 , which is in the magnetized, active state, supplies 600 positive and n due to its activation with an alternating field of 600 Hz per second egative impulses due to its permanent magnetization with the appropriate frequency. The induction coils 15 , 15 , in which the pulses are generated, pass this to a filter electronics 19 in which the inductors 15 , 15 applied to the signal are amplified and filtered out so that a signal is present at the output of the filter electronics 19 , which is fed to the computer 13 . The computer 13 first checks the probability of whether this signal is certainly also Wiegand pulses that were generated by a Wiegand wire serving as a sensor metal element 8 . For this purpose, the computer 13 calculates the amplitude ratio of the amplitude of a positive pulse and a subsequent negative pulse, which are very different if the field strength does not exceed an upper limit, which is approximately 25 A / cm in the exemplary embodiment shown. If the amplitude ratio in the present exemplary embodiment is at least 3: 1, the computer 13 assumes, on the basis of appropriate programming, that the impulses it detects come from an active, non-deactivated Wiegand wire, and triggers on a flashing light 20 an optical alarm and an acoustic alarm on a signal horn 21 , the entrance and exit doors of the supermarket optionally being able to be locked automatically if desired. The customer in question can then be subjected to a corresponding check.

If, on the other hand, the computer 13 detects Wiegand pulses, but on the other hand determines that their amplitude ratio is below the amplitude limit ratio of 3: 1 intended for triggering an alarm, the computer assumes that the label is deactivated, and therefore does not trigger an alarm. This is particularly the case when a Wiegand wire serving as a sensor metal element 8 has been deactivated in the area of the conveyor belt 5 by a magnetic alternating field which is initially very strong and then continuously decreases. In this demagnetized state, the amplitudes of positive and negative pulses are the same.

It is readily apparent that it can practically not trigger false alarms in the security system according to the Invention. For one thing, such Wiegand impulses are only generated by Wiegand wires, which are almost certainly not carried by customers. Even if this should be the case contrary to expectations, the corresponding Wiegand wire would still have to be in an activated state and the ratio of its positive and negative impulses (or vice versa) would have to exceed the limit value of 3: 1. All of this is practically impossible, so that an alarm is only triggered if a customer actually leads an appropriately secured item 2 past the cash register 4 to steal it.

As has already been explained above, the Wiegand wires can easily be glued to the goods 2 to be secured together with a conventional price tag 7 , an approximately 1 cm long Wiegand wire being completely sufficient, and its diameter being, for example, only 0 , 25 mm can be. Despite these small dimensions, a sensor metal element 8 designed in this way is not, for example, scratched with a fingernail or the like. to render ineffective.

As has already been explained above, such a Wiegand wire 8 then generates a relatively strong, easily evaluable pulse if its longitudinal axis does not deviate too much from the magnetic vector (see arrow 16 ) of the magnetic field generated by the field coil 9 . If a thief carries a correspondingly secured item 2 , the sensor metal element 8 of which, for example, happens to be in the vertical direction when passing through the control gate 1 , then coils 15 would not be induced in the induction coil by a sufficiently strong pulse. This can be accepted if, on the one hand, it can be assumed that the goods 2 to be secured are not very high-quality goods, and, on the other hand, it can be assumed that a thief will visit such a sales outlet more or less regularly, so that it can then be determined according to statistical principles on average every second or third theft and, after appropriate punishment, can be banned from the home.

If, on the other hand, you want to further increase security (e.g. because the goods to be secured are at least partially of higher quality), you could - as already explained above - possibly have a second field coil 9 and possibly even a third field coil 9 installed, the magnetic vector axes of which run at an angle (possibly at right angles) to one another, in which case the security of theft detection is increased accordingly. Another possibility is evident, however, that the installation is not provided in a correspondingly complex manner, but that higher quality goods are provided with two or three sensor metal elements 8 , the longitudinal axes of which are each at an angle, preferably at right angles, to one another. In this way, for example, the object 2.1 indicated in FIGS. 1 and 2 is secured, which is drawn out again partially enlarged in FIG. 2 at the top left. It can be seen that the goods 2.1 are provided with three security tags 7 , the sensor metal element 8 of which is designed as a Wiegand wire and extends at right angles to the two other Wiegand wires 8 , 8 . With such a security, a thief has no chance to cross the field coil 9 without triggering an alarm, since one of the Wiegand wires 8 is always in a parallel position or quasi-parallel position to the magnetic vector 16 of the field coil 9 . Such a fuse with several Wiegand wires 8 is reasonably priced, since the sensor-like metal elements 8 do not cost 6 to 25 pounds, as in the prior art, but 0.5 pounds, so that a material expenditure of less can be seen than half a penny is economically viable if practically one hundred percent theft protection can be achieved.

In order to increase the display security even further, the Wiegand wires serving as sensor metal elements 8 can optionally also be integrated into the goods 2 or their packaging, so that a potential thief who is familiar with such a security system has practically no possibility has to track down the sensor metal elements and, if necessary, remove them if he wants to steal a certain item 2 .

In spite of this unusually high alarm reporting security, a false alarm is practically impossible, since the computer 13 and the filter electronics 19 can easily be designed or programmed in such a way that other pulses, which originate from atmospheric disturbances or any electromagnetic interference pulses, are recognized or at the filtering are filtered out. Even if any metallic objects are brought into the area of the field coil 9 , which emit any pulses when magnetically excited, a distinction is also possible and given here, since - as stated - ultimately only with an asymmetrical amplitude ratio (certain size) An alarm is triggered, but the asymmetry of the positive and negative impulses is a special feature of the Wiegand effect or the Wiegand wire working according to or with this effect, which does not occur with any other metallic materials. A false alarm is accordingly only conceivable if a customer carries an active Wiegand element which is not a sensor metal element 8 of the security system. However, since Wiegand wires are only used in speed and flow meters, and it is not common to use such devices when shopping in a supermarket, visiting an exhibition or the like. a false alarm is practically excluded.

It is practical with the security system according to the invention all conceivable goods can be secured, with only the Securing strongly magnetic products (e.g. magnetic Cans) is problematic, since they may have an Er can prevent the Wiegand wire from moving.  

Except as described above and in the attached Drawing schematically illustrated embodiment, which refers to a supermarket can itself understandable also all possible other sales or Exhibition venues, libraries etc. with a fiction contemporary security system provided in an advantageous manner will.

As already explained above, is suitable the security system according to the invention can also be seen as Burglar alarm system, for example, also for private households. Are the outlets leading to the outside like Windows and doors, floor and cellar hatches etc. each provided with at least one field coil, which is then used moderately already during construction (possibly also later) in the wall surrounding the relevant room outlet or in the Ground is let in, and become the counter to be secured stands with (in as invisible a place as possible) Wiegand wire provided (in this case it goes without saying installation of numerous Wiegand wires also costs moderately easy to wear), then in an analogous way an alarm is triggered if one with at least one Wiegand Wire secured object through a room outlet is transported outside because it is then activated field coil a Wiegand coil in at least one induction coil Triggers a pulse that triggers after its detection of an alarm. A burglar trained in this way Security system is against known burglar-proof systems even more advantageous because they are such unrecognizable and practically unlegitimized Burglars can not be switched off, because the preference wise provided frequency generator at any ver stuck place of a house, an apartment or the like. so  can be installed so that it can hardly be found and since it is especially for larger objects for Burglar is practically impossible, according to Wiegand wires to look for, but you can never be sure whether they are working on a certain object (e.g. a cost baren piece of furniture, a carpet or the like) actually all found Wiegand wires if they did Security system is known as such and it, for example. three or four Wiegand wires from one item removed.  

Reference symbol list
(List of Reference Numerals)

1 control gate (= room outlet)
2 goods (objects to be secured)
3 customers
4 cash register
5 conveyor belt
6 cashier
7 Price tag = security label
8 metal sensor element (= Wiegand wire)
9 field coil
10 field coil
11 round
12 light barrier
13 computers
14 frequency generator
15 induction coils
16 arrow
17 middle (of 9 )
18 underground
19 filter electronics
20 flashing light
21 bugle

Claims (58)

1. Arrangement for securing in a room with at least one space outlet, in particular a (self-service) point of sale such as a supermarket, are union objects against theft or burglary, the objects to be secured each with at least one magnetic activatable sensor-metal element are provided with a to be arranged at each room outlet first device for generating a magnetic field, in the area of which a magnetically activated sensor element arranged on a respective object to be secured when a field strength limit value is exceeded Signal generated, and a second device associated with the first device, by means of which a signal is to be detected and supplied to an alarm device in order to trigger an alarm, characterized in that the sensor metal elements ( 8 ) are each designed to be in the active state in an area of the magnetic field in which di e field strength is greater than a lower limit, generate an atypical signal which is not generated by other metallic objects in the case of magnetic excitation, but is only generated by a magnetizable object if it has been subjected to a specific treatment; and that the first device consists of at least one (first) field coil ( 9 ), preferably with a horizontal central axis ( 16 ), which surrounds the relevant space outlet ( 1 ) in an annular manner, and whose height ( H ) and width ( B ) is designed such that that a person can cross it in the direction of its central axis ( 16 ). 2. Arrangement according to claim 1, characterized in that the sensor metal elements ( 8 ) generate a pulse by the magnetic field generated by the field coil ( 9 ) in the second device ( 15 , 15 ). 3. Arrangement according to claim 2, wherein the field coil generates a magnetic alternating field, characterized in that the sensor metal elements ( 8 ) upon excitation by the magnetic field of the field coil ( 9 ) in the second device ( 15 , 15 ) a quasi-stationary pulse produce. 4. Arrangement according to claim 3, characterized in that the sensor metal elements ( 8 ) each generate an asymmetrical metric pulse when excited by the alternating field generated by the field coil ( 9 ). 5. Arrangement according to one or more of the preceding claims, characterized in that the sensor metal elements ( 8 ) in the inactive state in a magnetic field corresponding field strength produce no or a qualitatively and / or quantitatively completely different signal than in the active state. 6. Arrangement according to one or more of the preceding claims, characterized in that the sensor metal elements ( 8 ) are each designed as Wiegand wire. 7. Arrangement according to claim 6, characterized in that the serving as sensor metal elements ( 8 ) Wiegand wires have a length of about 5 to 20 mm. 8. Arrangement according to claim 7, characterized in that the serving as sensor metal elements ( 8 ) Wiegand wires have a length of about 1 cm. 9. Arrangement according to one or more of claims 6 to 8, characterized in that the Wiegand wires serving as sensor metal elements ( 8 ) have a diameter of approximately 0.15 to 0.4 mm. 10. The arrangement according to claim 9, characterized in that the serving as sensor metal elements ( 8 ) Wiegand wires have a diameter of 0.25 mm. 11. The arrangement according to one or more of the preceding claims, characterized in that the height H of the (first) field coil ( 9 ) is approximately 2 m and its width ( B ) is approximately 1 m. 12. The arrangement according to claim 11, characterized in that the height ( H ) of the (first) field coil ( 9 ) is approximately 2.2 m and the width ( B ) of the field coil ( 9 ) is approximately 0.8 m. 13. Arrangement according to one or more of the preceding claims, characterized in that the leg cross section of the (first) field coil ( 9 ) carries about 5 to 15 cm ² be. 14. Arrangement according to claim 13, characterized in that the leg cross section of the field coil ( 9 ) is approximately 8 cm ² . 15. The arrangement according to one or more of the preceding claims, characterized in that the (first) field coil ( 9 ) or about 100 to 200 turns of copper wire. 16. The arrangement according to claim 15, characterized in that the field coil ( 9 ) has about 150 turns. 17. The arrangement according to one or more of the preceding claims, characterized in that the lower leg of the (first) field coil ( 9 ) is arranged sunk in the floor ( 18 ) or a wall of the room in question. 18. The arrangement according to claim 17, characterized in that the other legs of the (first) field coil ( 9 ) in a wall of the relevant space outlet ( 1 ) are left. 19. Arrangement according to one or more of the preceding claims, characterized in that the respective first device associated with a space outlet ( 1 ) has at least two field coils ( 9 , 9 ) whose central axes ( 16 ) or magnetic vectors run at an angle to one another. 20. The arrangement according to claim 19, characterized in that the central axes ( 16 ) or magnetic vectors of two field coils ( 9 , 9 ) assigned to a space outlet ( 1 ) run essentially perpendicular to one another. 21. The arrangement according to one or more of the preceding claims, characterized in that the at least one field coil ( 9 ) exciting frequency generator ( 14 ) generates a fre quency of approximately 400 to 800 Hz. 22. The arrangement according to claim 21, characterized in that the frequency generator ( 14 ) generates a frequency of approximately 600 Hz. 23. Arrangement according to one or more of the preceding claims, characterized in that the frequency generator ( 14 ) is to be switched on automatically when a person ( 3 ) approaches him, and / or is to be switched off automatically when a person ( 3 ) from him away. 24. The arrangement according to one or more of the preceding claims, characterized in that each field coil ( 9 ) is connected to a capacitive resistor, the resonance frequency of the system created by the inductance of the field coil ( 9 ) and the capacitance essentially equal to the excitation frequency of the Frequency generator ( 14 ). 25. The arrangement according to claim 24, characterized in that the capacitive resistor is connected in series with the inductance of the field coil ( 9 ). 26. The arrangement according to one or more of the preceding claims, characterized in that the frequency generator ( 14 ) is designed so that its frequency automatically on the respective resonance frequency of the system formed from the inductance of the field coil ( 9 ) and the connected capacitive resistance adjusts or settles. 27. The arrangement according to one or more of the preceding claims, characterized in that the second device has at least one induction coil ( 15 ). 28. The arrangement according to claim 27, characterized in that an induction coil ( 15 ) is arranged on two parallel legs of each field coil ( 9 ), the induction coils ( 15 , 15 ) being oriented so that they change the of the field coil ( 9 ) convert the generated magnetic field, the vector of which runs parallel to the central axis ( 16 ) of the field coil ( 9 ). 29. The arrangement according to claim 28, characterized in that the two induction coils ( 15 , 15 ) of a field coil ( 9 ) are arranged approximately at half the height of the leg ( h ). 30. Arrangement according to one or more of claims 27 to 29, characterized by induction coils ( 15 , 15 ) with low self-capacitance and / or without a metal core. 31. Arrangement according to one or more of the preceding claims, characterized in that the induction coils ( 15 , 15 ) is followed by an amplifier by means of which the signal applied to them is to be amplified. 32. Arrangement according to one or more of the preceding claims, characterized in that the induction coils ( 15 , 15 ) an electronic filter device ( 19 ) is arranged by means of which signals generated by a sensor metal element ( 8 ) are to be filtered out. 33. Arrangement according to one or more of the preceding claims, characterized in that the induction coils ( 15 , 15 ) or the amplifier or the filter device ( 19 ) is a computer ( 13 ) after or assigned, which is to be activated, when a person approaches a room outlet ( 1 ); that the computer ( 13 ) then controls the frequency generator ( 14 ); and that the computer ( 13 ), when receiving pulse signals, checks the probability that / whether these signals are a signal generated by a sensor metal element ( 8 ). 34. Arrangement according to claim 33 and claim 6 and possibly one or more of the other preceding claims, characterized in that the computer ( 13 ) inter alia checks the amplitude ratio of the positive and negative pulses and at a predetermined ratio of the positive to the negative pulses (or vice versa) triggers an alarm. 35. Arrangement according to claim 34, characterized in that the computer ( 13 ) triggers an alarm when the amplitude ratio is approximately 3: 1. 36. Arrangement according to one or more of the preceding claims, characterized in that only one computer ( 13 ) and / or only one frequency generator ( 14 ) is provided for all space outlets ( 1 ). 37. Arrangement according to one or more of the preceding claims, characterized in that when used as an anti-theft system in a shop, a deactivation device ( 10 ) for the sensor metal elements ( 8 ) is provided, which has a relatively strong magnetic field (possibly an alternating field ) which is reduced locally and / or temporally slowly and steadily. 38. Arrangement according to claim 37, characterized in that the deactivation device ( 10 ) on a conveyor belt ( 5 ) is arranged, which is present at a space outlet ( 1 ). 39. Use of a portion of a Wiegand wire or the like. as a sensor metal element ( 8 ) for a magnetic securing system for securing objects ( 2 ) against theft in a shop or the like. or against burglary theft. 40. metal sensor element for an arrangement according to one or more of claims 1 to 38 or for use according to claim 39, characterized in that it is in the active state in the range of a magnetic field in which the field strength is greater than a certain lower limit (= Ignition field strength), in a measuring device ( 15 , 15 ) generates an atypical signal for other metallic, possibly magnetizable objects. 41. Metal sensor element according to claim 40, characterized in that it generates a pulse when excited by a magnetic field in the measuring device ( 15 , 15 ). 42. Sensor metal element according to claim 40 or 41, characterized characterized in that when excited by a magnetic Alternating field generates a quasi-stationary pulse. 43. Sensor metal element according to one or more of the An sayings 40 to 42, characterized in that it at Er excitation by an alternating magnetic field an asymmetry generated momentum. 44. Sensor metal element according to one or more of the An Proverbs 40 to 43, characterized in that in corresponding active state in a magnetic field Field strength none or a qualitative and / or quantitative completely different signal generated than in the active state.   45. Sensor metal element according to one or more of the Claims 40 to 44, characterized by training as Wiegand wire. 46. Sensor metal element according to claim 45, characterized through a length of 5 to 20 mm. 47. Sensor metal element according to one or more of the An sayings 40 to 46, characterized by a length of approx. 1 cm. 48. Sensor metal element according to one or more of the An sayings 40 to 47, characterized by a diameter from approx. 0.15 to 0.4 mm. 49. Sensor metal element according to claim 48, characterized due to a diameter of approx. 0.25 mm. 50. Metal sensor element according to one or more of claims 45 to 49, characterized in that it has at least two Wiegand wires ( 8 , 8 ) arranged at an angle to one another. 51. metal sensor element according to claim 50, characterized in that the Wiegand wires ( 8 , 8 ) are substantially perpendicular to each other. 52. Sensor metal element according to claim 50 or 51, characterized in that three Wiegand wires ( 8 , 8 , 8 ) are provided. 53. Sensor metal element according to claim 50 or 51, characterized in that a plurality of hedgehog-shaped Wiegand wires ( 8 ) is provided. 54. Arrangement according to one or more of claims 1 to 5, characterized in that the sensor metal elements ( 8 ) are designed as so-called impulse wire, which have a composite wire in which an inner core is held by the jacket material under tension is, and a permanent magnet wire arranged approximately parallel to the composite wire of approximately the same length. 55. Sensor metal element according to one or more of the claims 40 to 44, characterized by training as an impulse wire, which has a composite wire, in which an inner Core held under tension by the jacket material is arranged, as well as one parallel to the composite wire Permanent magnet wire of approximately the same length. 56. Sensor metal element according to claim 55, characterized through a length of approx. 1 cm. 57. Sensor metal element according to claim 55 or 56, marked is characterized by a diameter of approx. 0.1 to 0.2 mm. 58. Sensor metal element according to claim 57, characterized due to a diameter of approx. 0.15 mm.